permlib::SchreierGenerator< PERM, TRANS > Class Template Reference

stateful generator of Schreier generators More...

#include <schreier_generator.h>

Inheritance diagram for permlib::SchreierGenerator< PERM, TRANS >:

Public Types
typedef std::list< typename PERM::ptr >::const_iterator	PERMlistIt
	const iterator to a list of PERMutations
typedef std::list< unsigned long >::const_iterator	TRANSlistIt
	const iterator to a list of points (unsigned long)

Public Member Functions
	SchreierGenerator (const TRANS *U, PERMlistIt S_begin, PERMlistIt S_end)
	constructor More...
PERM	next ()
	generates an element
bool	hasNext ()
	true, iff more elements can be generated
void	update (TRANS *U, PERMlistIt S_begin, PERMlistIt S_end)
	updates transversal and group generators that the Schreier generators are constructed from More...
void	update (unsigned int j)
	updates the state of this generator More...
Public Member Functions inherited from permlib::Generator< PERM >
virtual	~Generator ()
	virtual destructor

Detailed Description

template<class PERM, class TRANS>
class permlib::SchreierGenerator< PERM, TRANS >

stateful generator of Schreier generators

Constructs all Schreier generators from given transversal and generators.

The idea is something like forall(u in U) { forall(s in S) { buildSchreierGenerator(u,s); } } only that U and S can be updated without iterating over the same pair (u,s) twice, ensuring that every pair (u,s) is used at least once (if so many generators are requested via next() ).

Constructor & Destructor Documentation

SchreierGenerator()

template<class PERM , class TRANS >

permlib::SchreierGenerator< PERM, TRANS >::SchreierGenerator	(	const TRANS *	U,
		PERMlistIt	S_begin,
		PERMlistIt	S_end
	)

constructor

Parameters

U	transversal to build Schreier generators from
S_begin	begin iterator of group generating list to build Schreier generators from
S_end	begin iterator of group generating list to build Schreier generators from

Member Function Documentation

update() [1/2]

template<class PERM , class TRANS >

void permlib::SchreierGenerator< PERM, TRANS >::update	(	TRANS *	U,
		PERMlistIt	S_begin,
		PERMlistIt	S_end
	)

updates transversal and group generators that the Schreier generators are constructed from

Parameters

U	transversal to build Schreier generators from
S_begin	begin iterator of group generating list to build Schreier generators from
S_end	begin iterator of group generating list to build Schreier generators from

update() [2/2]

template<class PERM , class TRANS >

void permlib::SchreierGenerator< PERM, TRANS >::update

(

unsigned int

j

)

updates the state of this generator

Saves the current state. Before returning to the current state, all Schreier generators from S[j], S[j+1], &c. and the already visited transversals are next

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The documentation for this class was generated from the following file:

• include/permlib/generator/schreier_generator.h